diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/tst-rseq-tls-range.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/tst-rseq-tls-range.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/tst-rseq-tls-range.c b/sysdeps/unix/sysv/linux/tst-rseq-tls-range.c new file mode 100644 index 0000000..5891e5f --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-rseq-tls-range.c @@ -0,0 +1,195 @@ +/* Verify that TLS blocks and the rseq area do not overlap. + Copyright (C) 2025 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <array_length.h> +#include <elf.h> +#include <link.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/xdlfcn.h> +#include <sys/auxv.h> +#include <sys/param.h> +#include <sys/rseq.h> +#include <thread_pointer.h> +#include <unistd.h> + +/* Used to keep track of address ranges. The ranges are sorted and + then checked for overlap. */ + +struct address_range +{ + const char *prefix; + const char *label; + uintptr_t start; + size_t length; +}; + +struct address_range ranges[20]; +size_t range_count; + +static void +add_range (const char *prefix, const char *label, + const void *start, size_t length) +{ + TEST_VERIFY (start != NULL); + TEST_VERIFY (length > 0); + TEST_VERIFY_EXIT (range_count < array_length (ranges)); + ranges[range_count].prefix = prefix; + ranges[range_count].label = label; + ranges[range_count].start = (uintptr_t) start; + ranges[range_count].length = length; + ++range_count; +} + +static int +range_compare (const void *a1, const void *b1) +{ + const struct address_range *a = a1; + const struct address_range *b = b1; + if (a->start < b->start) + return -1; + if (a->start > b->start) + return 1; + return 0; +} + +static void +check_for_overlap (void) +{ + qsort (ranges, range_count, sizeof (ranges[0]), range_compare); + uintptr_t previous_end = ranges[0].start + ranges[0].length - 1; + for (size_t i = 1; i < range_count; ++i) + { + uintptr_t this_end = ranges[i].start + ranges[i].length - 1; + if (ranges[i].start <= previous_end) + { + puts ("error: overlap between address ranges"); + printf (" %s%s: [0x%lx, 0x%lx)\n", + ranges[i - 1].prefix, ranges[i - 1].label, + (unsigned long int) ranges[i - 1].start, + (unsigned long int) previous_end); + printf (" %s%s: [0x%lx, 0x%lx)\n", + ranges[i].prefix, ranges[i].label, + (unsigned long int) ranges[i].start, + (unsigned long int) this_end); + } + previous_end = this_end; + } +} + +static void +add_rseq (void) +{ + /* The initial size of 32 bytes is always allocated. The value + reported by __rseq_size does not include the alignment, which can + be larger than 32 if requested by the kernel through the + auxiliary vector. */ + size_t size = 32; + if (__rseq_size > 0) + size = roundup (__rseq_size, MAX (getauxval (AT_RSEQ_ALIGN), 32)); + + printf ("info: adding rseq area of %zu bytes\n", size); + add_range ("", "rseq area", + (char *) __thread_pointer () + __rseq_offset, size); +} + +/* These functions add the TLS data for all loaded modules to the + recorded address ranges. */ + +static int +dlip_callback (struct dl_phdr_info *info, size_t size, void *ignored) +{ + /* If the dynamic linker does not provide TLS address information, + there is nothing to register. */ + if (info->dlpi_tls_data == NULL) + return 0; + + for (int i = 0; i < info->dlpi_phnum; ++i) + { + if (info->dlpi_phdr[i].p_type == PT_TLS) + { + printf ("info: adding TLS range for \"%s\" (%zu bytes)\n", + info->dlpi_name, (size_t) info->dlpi_phdr[i].p_memsz); + add_range ("TLS for ", + info->dlpi_name[0] != '\0' ? info->dlpi_name : "main", + info->dlpi_tls_data, info->dlpi_phdr[i].p_memsz); + break; + } + } + return 0; +} + +/* Returns true if any TLS ranges were found. */ +static void +add_tls_ranges (void) +{ + dl_iterate_phdr (dlip_callback, NULL); +} + +volatile __thread int thread_var __attribute__ ((aligned (MAIN_TLS_ALIGN))); + +static int +do_test (void) +{ + void *original_brk = sbrk (0); + void *initial_allocation = malloc (16); + + /* Ensure that the variable is not optimized away. */ + thread_var = 0; + + printf ("info: rseq area size: %u\n", __rseq_size); + + puts ("info: checking address ranges with initially loaded modules"); + add_range ("", "program break", original_brk, 1); + add_range ("", "malloc allocation", initial_allocation, 16); + add_rseq (); + add_tls_ranges (); + printf ("info: %zu ranges found\n", range_count); + check_for_overlap (); + range_count = 0; + + puts ("info: checking address ranges after dlopen"); + void *handle = xdlopen ("tst-rseq-tls-range-mod.so", RTLD_NOW); + int *mod_thread_var = xdlsym (handle, "mod_thread_var"); + add_range ("", "program break", original_brk, 1); + add_range ("", "malloc allocation", initial_allocation, 16); + add_rseq (); + add_tls_ranges (); + { + bool found_objects = false; + for (size_t i = 0; i < range_count; ++i) + if (strchr (ranges[i].label, '/') != NULL) + found_objects = true; + if (!found_objects) + /* __tls_get_addr does not fully work with static dlopen. + Add some fall-back test data. */ + add_range ("", "mod_thread_var", + mod_thread_var, sizeof (*mod_thread_var)); + } + printf ("info: %zu ranges found\n", range_count); + check_for_overlap (); + xdlclose (handle); + + free (initial_allocation); + return 0; +} + +#include <support/test-driver.c> |